Boiler for treating wood



(No Model.) I

J. MAKIN.

BOILER FOR TREATING WOOD, 6170., PORPAQPER PULP. No. 385,943. Patented Feb; 9, 1886.

Fit :1.

NITED STATES JOHN MAKIN, OF GLOSSOP, COUNTY CHARLES OHESLEY SPRINGER,

PATENT OF DERBY, ENGLAND, ASSIGNOR TO OF BOSTON, MASSACHUSETTS.

SPECIFICATION forming part of Letters Patent No.335,943, dated February 9, 1886.

Application filed July 29, 18-5.

To all whom it may concern.-

Be it known that LJOHN 1\ IAKIN,0fG1OSSOp, county of Derby, England, have invented an 'Improvei'nent in Boilers for Treating Wood,

5 &c., for Paper and other Pulp, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

In the product-ion of fiber suitable for use, among other things, as paper-pulp, wood and other eelulose or fiber-yielding material placed in an iron or steel boiler is subjected to the action of an alkali and heat.

Instead of employing an alkali it has recently been found that wood and other fiberyielding material may be better treated in an acid-such, for instance, as an acid sulphite of lime; but acid cannot be practically used in the ordinary iron boilers, for the acid acts upon and eats the iron, blackening the pulp, and destroying the boiler.

To enable an iron or steel boiler to be used with acid solutions, it must be lined with lead 7 '25 or an equivalent acid'resisting compound composed in whole orin part of lead of commerce.

Lead linings have heretofore been applied to metal boilers in many ways,among which are the followiug,viz: Sheet-lead has been attached directly to the interior of the boiler by means of a flux or alloy; sheet-lead has been placed against the interior of the boiler, and has had its edges bent in between sections of the boil- ,ersheets and been bolted in place; sheet-lead 3 5 has been held against the interior of the boiler by means of hoops or bands of iron covered with lead, and sheet-lead has been connected directly with the material of the boiler by means of bolts covered with lead, the bolts 02c 40 tending through the boiler and receiving nuts. Other attempts have been made to apply a lead lining directly to the metal of the boiler.

In methods known to me prior to my invention thereof the sheet-lead lining has al- 5 ways been applied. directly to the interior of the boiler; but in all plans prior to my invention great difficulty has been experienced in retaining the sheet lead lining in place in the boiler, the lining creeping or moving in the boiler and detaching itself from the inner side thereof. This difficulty has Serial No. 172,933. (No model.)

been experienced because of the fact that lead and iron expand unequally when subjected to like temperature, or the lead. when heated and expanded has not the property of con 5 tracting and assuming its original size, as in the case of iron or steel. This unequal expansion or contraction of the metals and the creeping of the lead lining is aggravated each time the boiler is heated to treat a mass of 6:) wood or other fiber-producing material in an acid or other hot solution, and with the lead lining applied directly to the boiler, and as practiced before my invention,and so far as known to me, the care required to keep the lining in repair and in place is so great as to render the use of an acid solution almost impractical in a commercial sense; hence I have made experiments having especially for their aim the production of alining which,applied within an iron boiler of usual construction, would not creep and would be durable. I have accomplished this desired result by making a compound lining composed of-two metals, each having a different rate of expansion, the one of least expansion giving the necessary stiffness and strength to the lining,while the oth er resists the action of the acid.

In the embodiment of my invention as herein contained a foundation plate of metal, preferably iron, is covered on both sides with lead or with an acid-resisting or non-corrosive metallic compound, the iron being preferred because of cheapness, and because it expands at the same rate of speed as the boiler and at a less rate than the lead face, and, as herein shown, the foundation-plate is perforated, forming holes, through which the: lead at each side may be tied or anchored to the foundatiouplate at short distances-apart, such plan 0 serving to hold the lead in place practically and durably, notwithstanding the inability of the lead, when cooling, to resume its original size. Preferably, the tying or anchoring of lead to the foundation-plate or central core will be done by means of bolts or spurs integral with the lead or other equivalent acid-v resisting metal nsed for the faces or sides of the lining, and the faces will be applied by casting the lead upon the foundation-plate while the latter is supported in a mold, the lead covering both sides of the foundationplate andentering the holes therein, the compound lining so produced being in pieces or sections of suitable shape and size to fit the boiler with which it is to be used. This lining is shown in Letters Patent of the United States granted to me on the 17th day of February, 1885, and numbered 312,485.

My invention in boilers for the treatmentof wood and other fiber-yielding material for the production of fiber for paper-pulp and other purposes consists in the combination, with a closed metal boiler or vessel, of a compound lining composed of two metals having different rates of expansion, the metal having the least degree of expansion under like temperature being employed for the foundation-plate, the metal of greater expansion constituting the sides or faces of the compound lining, and being composed of lead or equivalent acidresisting non-corrosive metal, the metal having the greater degree of expansion being tied or anchored to the foundation at frequent intervals to obviate the objectionable creeping of the lead or acid-resisting faces of the lining; also, in an apparatus for the production of paper-pulp, the combination, with aboiler, of a compound lining composed of a foundationplate of hard metal or iron and a soft or more easily fused acid-resisting metallic face applied to the foundation -plate and anchored or tied to it at frequent intervals,to neutralize or overcome the creeping of the lining within the boiler, substantially as will be described.

Figure 1, in elevation partially broken out, represents a sufficient portion of a boiler used in pulp'making to enable my invention to be understood; and Fig. 2, an enlarged detail of the boiler and its attached compound lining.

The boiler A is composed of sheets of wrought iron or steel riveted together in usual manner to constitute a boiler or shell.

The boiler herein shown is substantially spherical, and at one part of its periphery has a man -hole, B, provided with a removable cover-plate, B, and at another portion a delivery, O, provided with a suitable valve, 0.

The boiler herein shown is adapted to rotate, and therefore has journals D D, the journal D being hollow to receive through it a pipe (shown in dotted lines) by which to introduce steam or hot liquid to treat the wood or other material in the boiler. The journal I) has attached to it a stud, to which is secured the large gear D", which, engaged and driven by gearing, as usual, causes the boiler to be rotated.

The parts so far as described are of usual construction, and instead of a boiler of the particular shape shown, I may employ a boiler of any other shape commonly used for treating wood, &c., for paper-pulp.-

My improved compound lining is composed, as herein shown, of a foundation-plate,

The compound lining will be applied to the boiler in sections, each preferably shaped to correspond with that part of the boiler where it is to be placed, and the several sections, placed in the boiler with their edges abutting, will be burned or soldered together or otherwise treated to form a liquid-tight joint between adjacent sections of the compound lining.

If desired, the meeting edges of the sections may be covered with strips 6 of sheet-lead or acid-resisting alloy, which may be soldered to the sections to cover the joints, as designated by the heavy black line in Fig. 1.

I do not desire to limit my invention to the lining of boilers of the particular shape herein shown, for while I prefer a spherical boiler, my compound lining is well adapted to line boilers of any usual shape. The sections of compound lining will be held firmly inside the boiler-shell, and the foundation will enable the sections applied in the boiler to be kept in place.

I claim- 1. In an apparatus for the treatment of wood and other fiber-yielding material for paper-pulp and other uses, a boiler combined with a compound lining composed of two metals having different rates of expansion or contraction, the metal having the least expansion constituting the foundation-plate for the compound lining, the metal of greatest expansion or least contraction constituting the sides or faces of the compound lining, and being composed of lead or equivalent acid-resisting or non-corrosive material, the latter metal being tied or anchored to the foundation-plate at frequent intervals, to thus obviate the objectionable creeping of the metal of. greatest expansion, substantially as described.

2. In an apparatus for the production of paper-pulp, the combination, with aboiler,of a compound lining composed of a foundation plate ofhard metal or iron and a soft or more easily fused acid-resisting metallic face applied to the foundation-plate and anchored or tied to it at frequent intervals,to neutralize or overcome the creeping of the lining within the boiler, substantially as described.

JOHN MAKIN.

Witnesses:

GEORGE DAVIES, CHARLES DAVIES. 

